The present invention relates to a developing apparatus and an image forming apparatus, which are built in, for example, a photocopier or a printer in which electronic photography is applied.
A photocopier or printer of the above-mentioned type includes a photosensitive member for carrying an electrostatic latent image. As a developer is applied to the electrostatic latent image carried on the photosensitive member by the developing apparatus, the latent image is visualized.
A developing apparatus includes a developing roller for supplying a developer and a layer thickness regulating blade for regulating the thickness of a layer of the developer on the developing roller, to keep the thickness at constant.
In general, a layer thickness regulating blade has a structure in which a flat-plate elastic member is adhered with an adhesive to a metal plate having a straight shape, and the elastic member is set to be in contact with the photosensitive member.
However, the conventional layer thickness regulating blade entails the following drawbacks.
That is, in the case where the metal plate to which the elastic member is adhered is thick, such a thick plate will not substantially exhibit a physical property as a plate spring, and therefore the contact force of the elastic member with respect to the developing roller is greatly influenced by variations between developing apparatus which result during the assembly. For this reason, it is conventionally difficult to control the contact force of the elastic member with respect to the developing roller at a constant value.
On the other hand, in the case where the metal plate of the thickness regulating blade is thin, it is possible to control the pressure force of the elastic member by utilizing the physical property of the plate spring. However, if the metal plate is thin, such a phenomenon that the metal plate itself is distorted due to expansion/contraction due to the hardening of the adhesive, frequently occurs.
If the metal plate is thin, it can be easily deformed, and therefore the elastic member cannot be pressed on the metal plate at a high pressure during the adhesion of the elastic member. Consequently, the adhesive cannot be applied evenly on the adhesion surface of the elastic member, resulting in, for example, uneven application of the adhesive.
Further, when the metal plate is of a shape other than a straight type, it is very difficult to evenly apply the adhesive on the adhesive surface.
These drawbacks appear as a cause for the uneven density of a toner image on a photosensitive member, which will create a further serious problem.
The present invention has been achieved as a solution to the above-described problem and the object thereof is to provide a developing apparatus and an image forming apparatus, which do not create a distortion in the support sprint member or do not cause an uneven adhesion or the like even if the metal-made support spring member is thin, but capable of that an elastic member is mounted properly.
According to the present invention, there is provided a developing apparatus comprising: a developing agent supplying device for supplying a developing agent to an electrostatic latent image carried on an image carrier such as to visualize it; and a layer thickness regulating device for regulating a thickness of a layer of the developing agent on the developing agent supplying device to a constant thickness, wherein the layer thickness regulating device further comprises a metal-made support spring member, and an elastic member set on the support spring member via a metal-made substrate having a thickness larger than that of the support spring member, such as to be brought into contact with the developing agent supplying device.
According to the present invention, there is further provided a developing apparatus comprising:
a latent image forming device for forming an electrostatic latent image on an image carrier;
a developing device for supplying a developing agent to the electrostatic latent image such as to visualize it; and a transfer device for transferring a visualized image visualized by the developing device onto a transfer member, wherein the developing device further comprises a developing agent supplying device for supplying a developing agent to the electrostatic latent image carried on the image carrier such as to visualize it; and a layer thickness regulating device for regulating a thickness of a layer of the developing agent on the developing agent supplying image to a constant thickness, wherein the layer thickness regulating device further comprises a metal-made support spring member, and an elastic member set on the support spring member via a metal-made substrate having a thickness larger than that of the support spring member, such as to be brought into contact with the developing agent supplying device.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.